Vermont: Stowe is sick-good terrain, good park, good snow, but expensive. Jay Peak is absolutely the best for terrain and snow but kind of in the middle of nowhere, although they have a waterpark now? if you're going with your fam. Killington is huge, Mt. Snow has a sick park.
New Hampshire: Vermont is better but loon has a good park, Cannon is sick, definitely the best terrain in NH.
Maine: Sunday River is my home mtn, huge, good parks, good skiing if you go the right spot, Sugarloaf is also huge, and has great terrain and good park. I don't know much about saddleback but it sounds sick.
If it was my choice I'd go to Jay Peak, Cannon, or Sugarloaf, but if you are concerned about park then Mount Snow, Loon, Sunday River/Loaf